Lesson 1: Getting Started
Is She Pregnant?
From the time your mare is covered you will be counting days. Count the days to the next scheduled heat cycle, count the days until you can ultrasound, count the days (and months) for vaccination schedule, and finally, counting the days until the birth of your long awaited foal.
There are many ways of determining pregnancy. For years horsemen have had a veterinarian palpate rectally to feel the mare’s uterus. The drawback is that they cannot tell until about forty days past conception. By that time you may know yourself, since your mare would have cycled again in about twenty days after he last covering. Blood serum and urine tests have also been used, but by far the most accurate and timely method is the ultra sound. A vet can tell by the eleventh day after conception if there is a viable fetus. Usually it is recommended to check on the seventeenth or eighteenth day for pregnancy and to check for multiple fetuses.
Multiple pregnancies are not desirable. Maybe you’ve seen pictures in a magazine, but the reason they make it in the magazine is because it is uncommon for multiple pregnancies to have a favorable outcome. If you ultrasound on the seventeenth or eighteenth day after ovulation and it is determined that the mare is carrying more then one fetus, you can decide to terminate the pregnancy. Since the fetuses have not adhered to the uterine wall at this time, there is some success in pinching off one foal and hoping the mare only aborts the one. Even if you are not so lucky, it is still not too late to rebreed the mare. If the mare is pregnant with twins, it is likely that she will abort them both between the fifth and eighth month.
Finally how do you determine the delivery or due date? The gestation period of a mare is between 330 to 350 days, but the majority foal between 332 and 348 days. However, unlike other mammals, such as your dog, which can be predicted almost to the day, there is no absolute determination of a due date. A mare is influenced by hereditary factors, her environment, and by the stallion’s genetics. There is also some influence by climatic conditions in certain regions in certain years.
Many horse breeders will tell you about eleven months, but I usually add ten or eleven days to that date. As you get to know your mare (assuming you breed her more then once) you may learn her normal pattern over the years. I have one mare, who to date, has delivered eleven moths to the day with each foal.
